title: Extremely low loss phonon-trapping cryogenic acoustic cavities for future physical experiments.
abstract: Low loss Bulk Acoustic Wave devices are considered from the point of view of the solid state approach as phonon-confining cavities. We demonstrate effective design of such acoustic cavities with phonon-trapping techniques exhibiting extremely high quality factors for trapped longitudinally-polarized phonons of various wavelengths. Quality factors of observed modes exceed 1 billion, with a maximum Q-factor of 8 billion and Q × f product of 1.6 · 10(18) at liquid helium temperatures. Such high sensitivities allow analysis of intrinsic material losses in resonant phonon systems. Various mechanisms of phonon losses are discussed and estimated.
authors.affiliation: Department of Time and Frequency, FEMTO-ST Institute, ENSMM, 26 Chemin de l'Épitaphe, 25000, Besançon, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Galliou
authors.forename: Maxim
authors.initials: M
authors.lastname: Goryachev
authors.forename: Roger
authors.initials: R
authors.lastname: Bourquin
authors.forename: Philippe
authors.initials: P
authors.lastname: Abbé
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Aubry
authors.forename: Michael E
authors.initials: ME
authors.lastname: Tobar